Public participatory geographic information systems (PP GIS) aim at enlarging citizen’s involvement and participation in decision-making processes. In this paper we review existing online PP GIS applications and present the framework of our analysis. We concentrate on the aspects of interactivity of such applications and the GIS functionalities needed for their operation. First results of ongoi...

This paper studies the one-way communication complexity of the subgroup membership problem, a classical problem closely related to basic questions in quantum computing. Here Alice receives, as input, a subgroup H of a finite group G; Bob receives an element y ∈ G. Alice is permitted to send a single message to Bob, after which he must decide if his input y is an element of H. We establish the f...

This paper studies the gap between quantum one-way communication complexity Q(f) and its classical counterpart C(f), under the unbounded-error setting, i.e., it is enough that the success probability is strictly greater than 1/2. It is proved that for any (total or partial) Boolean function f , Q(f) = ⌈C(f)/2⌉, i.e., the former is always exactly one half as large as the latter. The result has a...

1 Overview We continue discussing the distinct elements problem. Recall that in this problem, you receive as input a stream S = (x 1 , x 2 ,. . .), with each x i ∈ [n], and you are supposed to compute k = #{v ∈ [n] : v appears in S}. Topics for today: • Review of the algorithm from last lecture. • The LogLog algorithm, which is more space efficient. • Generalizing the algorithm from last lectur...

Kravtsev introduced 1-way quantum 1-counter automata (1Q1CAs), and showed that several non-context-free languages can be recognized by bounded error 1Q1CAs. In this paper, we rst show that all of these non-context-free languages can be also recognized by bounded error 1PR1CAs (and so 1Q1CAs). Moreover, the accepting probability of each of these 1PR1CAs is strictly greater than, or at least equa...